Can only duplicate display, doesn't work on its own?

[llama_egg]

Hey everyone, I'm pulling my hair out to figure out whats going on with my parents computer.

A bit of background, it's running Windows 10, 64bit, and is running a ATI HD 4800 series card, old, but for what they use it for it does the job. I've tried completely wiping the drivers and manually installing it but still nothing.

They recently bought a Acer xf240h, which, when plugged in, won't display anything UNLESS we also plug in the other display, then they mirror and it works, but if you try and extend, or disable the other display the acer stops working all together. It's the nuttiest thing and I just can't figure it out. Basically if the old display is plugged in and is working, both work, if we remove the old display on anyway, the new one won't display anything.

Any ideas?

 

[Barty1884]

How are you connected to the monitor(s)?

If you only have the option to mirror the primary monitor, I assume you're using a splitter?

 

[llama_egg]

No splitter, both are connected through DVI to the GPU.

 

[Barty1884]

Separate DVI connections?

 

[llama_egg]

Yessir, both different cables, taking up slot one and two on the card. Tried different cables and changing the slots, didn't change anything.

 

[Barty1884]

Which card do you have, specifcially? 4800 is a series.

Sounds like the DVI don't operate independently. Might have to try an active HDMI/DisplayPort to DVI (or whatever ports are available on the card).

 

[llama_egg]

It's a 4890. And I'm not sure if that would be the issue, because then the new monitor should work on its own, but it won't work at all without the other display connected.

 

[Barty1884]

Hmmm, odd. A 4890 can drive dual (independent) displays, and only has the 2x DVI ports.

Honestly, I'm not sure.

 

[llama_egg]

Exactly! It's baffling me, banging my head against this and nothing is adding up. Thanks for trying though.

 

[USAFRet]

Do you have an answer yet? I'm having this same problem and I have no idea

2 years later...please create a NEW thread for your particular situation.